Statistical Analysis Data will be assessed according to the intention-to-treat principle. Because the scope of the study is non-metastatic colon cancer, patients in whom metastases are detected intra-operatively will not be included in the analyses of long-term outcome. Survival is calculated from surgical resection of primary tumour to the last visit or death. For cancer-related survival, patients who die from other causes will be censored from the study at time of death. Probability curves will be constructed with the Kaplan-Meier method and compared with the log-rank test.